gpg failed to sign the data fatal: failed to write commit object [Git 2.10.0]

gpg failed to sign the data fatal: failed to write commit object [Git 2.10.0]

git github gpg-signature

git

Should I keep gitconfig's "signingKey" private?

git gnupg gpg-signature

git

Why does git sign with GPG keys rather than using SSH keys?

git digital-signature ssh-keys public-key gpg-signature

git

manage 2 git users gpg key and choose gpg sign per user

git gpg-signature

git